This invention relates to a sensing assembly for use with in a blasting system. In particular the invention relates to a sensing assembly that is operable to actuate an electronic detonator upon sensing a shock tube event without exposing a sensor on the assembly directly to a physical process resulting from signal propagation by a shock tube.
WO2012/009732 describes a timing module for use within a detonating system which includes discriminating and validating arrangements which sense and validate parameter characteristics produced by a shock tube event, and an electronic timer which executes a timing interval in response thereto. An end of a shock tube is connected via a coupling to a housing which contains the timing module. Various sensors are arranged in the coupling so that the sensors are exposed to a shock tube event resulting from signal propagation by the shock tube.
The shock tube event produces gasses and particles at high pressures and high temperatures which can be sufficiently severe to damage the sensors which are exposed to the event, before the sensors can complete their detecting and sensing functions and relay data thereon to downstream electronic circuiting. This, in turn, can result in a malfunction of the detonator.
An aim of the invention is to provide a sensor assembly to address, at least in part, the aforementioned situation.